RESULTS: Chromosome 1p/19q codeletion was observed in 19 of 41 patients (46%) via Fluorescent In Situ Hybridisation (FISH)
technique. Twenty-six patients (63%) showed positive immunoreaction with anti-IDH1 antibody. Six patients (15%) showed
positive immunoreaction with anti-p53 antibody. A statistically significant correlation was determined between chromosome
1p/19q codeletion and IDH1 mutation (p<0.0001). The patients who had tumors with chromosome 1p/19q codeletion and p53
overexpression were mutually exclusive. The mean estimated Progression Free Survival (PFS) of the patients who had tumors
with chromosome 1p/19q codeletion and/or IDH1 mutation was determined to be significantly longer than that of the patients
without these genetic changes, regardless of the treatment modality (p=0.006, p=0.004). PFS of the patients who received adjuvant
chemotherapy and whose tumors had chromosome 1p/19q codeletion or IDH1 mutation was significantly longer than that of the
patients without these genetic changes (p=0.001, p<0.0001).